Bannon, who previously served as Trump's chief strategist in the White House, had already come out in support of former state Supreme Court Justice Roy Moore, who is leading Strange in the polls. Trump endorsed Strange and will travel to Alabama on Friday to campaign for him.

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Breitbart news editor Matthew Boyle reportedly told reporters that "the only story that matters until next week is Alabama."

"As of now, everyone is working on the Alabama race. If anyone has any questions please let me know,” Boyle wrote in a Slack message to staffers obtained by CNN.

Bannon, Boyle and Breitbart spokespeople did not return CNN’s requests for comment.

At least six stories about Moore were featured on the Breibart home page as of Tuesday evening.

Bannon has stepped up his attacks against the GOP establishment since leaving the White House last month.